There is considerable interest in product recycling, and in particular, recycling of beverage cans made of aluminum. However, there are problems in preparing aluminum beverage cans for recycling. In preparation of the original cans for sale, the cans are printed with labeling information to identify the product and producer and impart necessary information to the consumer. Typical printing formulations are often lacquer coatings which adhere to the aluminum can and also for aesthetic purposes. Aluminum cans are overcoated with lacquers to protect the labeling material. Interiors are coated with FDA approved polymetric formulations to maintain product integrity. In order to recycle the can, these coatings must be removed.
There are various procedures proposed by the prior art to delacquer aluminum can stock. Many of these procedures are not environmentally satisfactory and therefore not usable commercially because they produce volatile organic hydrocarbons (VOCs) and/or release hazardous air pollutants (HAPs). Disposal of these solutions can be costly due to their compositions. Accordingly, there is a need in the art to provide compositions and methods for delacquering of aluminum cans which are environmentally friendly.
U.S. Pat. No. 5,246,116 of the present applicant discloses the use of polyalkylene glycol polymer solutions for the separation and recovery of aluminum foils, polymer films and coatings and papers in waste foil-containing laminates, such as packaging waste. The alkylene glycol polymer solution is used in combination with density and flotation separation techniques for complete component separation and recovery.
U.S. Pat. No. 4,692,263 to Eberhardt et al. discloses a stripping paste for removing lacquer from paint coatings which uses a combination of a diethylene glycol monoalkyl ether, a sodium salt of a C.sub.14 -C.sub.18 fatty acid, water, and optionally, nonionic or anionic wetting agents.
U.S. Pat. No. 4,365,993 to Meredith discloses a process for recovering aluminum from lacquer coated scrap by application of a mixture of halide salts before the lacquer coating is pyrolyzed. This is the type of process which may cause the generation of volatile organic carbons or hazardous air pollutants which the present invention avoids.
U.S. Pat. Nos. 4,600,513 and 4,746,422 disclose processes for detackification and clarification of over-sprayed paints and lacquers by use of halogenated hydrocarbons to separate a mixture of plastic particles and contaminants. U.S. Pat. No. 3,748,176 discloses a reclaiming process for aluminum substrates for disks.
The present invention provides a composition and method which overcome problems of the prior art.